On Wednesday at 9:54 p.m. the NWS Los Angeles/Oxnard CA issued a wind advisory valid from 10 p.m. until Thursday 6 p.m. The advisory is for Interstate 5 Corridor, Western San Gabriel Mountains and Highway 14 Corridor and Eastern San Gabriel Mountains.

By the time the winds get to the point where the Eaton Fire broke out in Altadena on Jan. 7, it’s not uncommon for them to have less than 5 percent relative humidity, meaning essentially no moisture at all.

The state is seeing a sharp water divide this year, with lots of rain in the north while the south has stayed dry. A hydrologist explains what’s happening.